What would it take to tip the U.S. economy back into recession? According to economists at Goldman Sachs, a rise of a couple tenths of a percentage point in the unemployment rate would do the trick.

The rule of thumb offers reason to pay close attention when the government reports this Friday on the state of the labor market in July. The three-month average of the unrounded unemployment rate currently stands at 9.07 percent, up from a low of 8.90 percent in April. If it hits 9.3 percent in July and stays at that level in August, the rule points to a double-dip recession.